Fix for highlighting 'abstract' in ClassTypeAlias.

pkg/analysis_server/test/analysis/notification_highlights_test.dart

Index: pkg/analysis_server/test/analysis/notification_highlights_test.dart
diff --git a/pkg/analysis_server/test/analysis/notification_highlights_test.dart b/pkg/analysis_server/test/analysis/notification_highlights_test.dart
index 7be135a9644cee3b6504fe5d7d8b929ca67bc621..773d6f65a8f17648b5c0264402c132a94d9fadbe 100644
--- a/pkg/analysis_server/test/analysis/notification_highlights_test.dart
+++ b/pkg/analysis_server/test/analysis/notification_highlights_test.dart
@@ -136,11 +136,13 @@ const AAA = 42;
   test_BUILT_IN_abstract() {
     addTestFile('''
 abstract class A {};
+abstract class B = Object with A;
 main() {
   var abstract = 42;
 }''');
     return prepareHighlights().then((_) {
-      assertHasRegion(HighlightRegionType.BUILT_IN, 'abstract class');
+      assertHasRegion(HighlightRegionType.BUILT_IN, 'abstract class A');
+      assertHasRegion(HighlightRegionType.BUILT_IN, 'abstract class B');
       assertNoRegion(HighlightRegionType.BUILT_IN, 'abstract = 42');
     });
   }